Illuminated multiscale dial structure



N0V- 25, 1952 L. G. MALHElRos ET AL 2,619,058

ILLUMINATED MULTISCALE DIAL STRUCTURE Filed Sept. 8, 1949 Inventors: "Luiz G.M-a|heros,` Lloyd E. Moncref,

Their Attorney.

Patented Nov. 25, 1952 ILLUMINATED MULTIS CALE DIAL STRUCTURE Luiz G. Malheiros, Syracuse, and Lloyd E. Moncrief, North Syracuse, N. Y., assignors to General Electric Company, a corporation of New York Application September 8, 1949, Serial No. 114,502

2 Claims. 1

Our invention relates to an illuminated multiscale dial structure for electrical indicating instruments and the like, in which the indicia of the various scales are selectively illuminated to indicate a particular scale to be utilized. It may, for example, be incorporated in a multi-band radio receiver.

It is a primary object of our invention to provide an improved illuminated multi-scale dial structure in which only the indicia of selected scales are indirectly illuminated in accordance with the operation of a scale-selecting switch mechanism.

Another object of our invention is to provide an improved multi-scale dial structure in which one selected group of scale indicia are indirectly back-lighted so as to stand out prominently in relief against an illuminated background.

Still another object of our invention is to provide an improved illuminated multi-scale dial structure in which an optical system for illuminating one scale at a time is electrically controlled and has no mechanically-moving parts.

A still further object of our invention is to provide an improved multi-scale dial structure which is simple and economical to construct and which provides a scale assembly which is pleasing in appearance and easy to read.

Another object of our invention is to provide an eicient means for illuminating a multi-scale dial structure which requires a minimum number of light source and maintains a uniform light distribution throughout the selected illuminated scale.

For additional objects and advantages, and for a better understanding of the invention, attention is now directed to the following description and accompanying drawings. The features of the invention believed to be novel are particularly pointed out in the appended claims,

In the drawings:

Fig. 1 is a fragmentary perspective view, partially cut away to show internal details of construction, of a dial structure embodying the invention;

Fig. 2 is a vertical cross-section view of the structure of Fig. l, looking towards the left at the plane 2 2;

Fig. 3 is a top plan view, partly in section, of the dial structure of Fig. 1; and

Fig. 4 is a simpliiied circuit diagram of the switching mechanism and power circuits for selectively energizing the electric lamps which illuminate the several scales in the structure of Figs. l, 2 and 3.

Corresponding elements in the several iigures (Cl. 11S-124.4)

of the drawings have been designated by corresponding reference numerals.

In Fig. l, our invention is represented as applied to a dial mechanism for a multi-band radio receiver. The mechanism is supported from a common mounting plate l] which is adapted to be bolted or otherwise secured to a radio receiver chassis or cabinet. Against the iront face of the mounting plate l0 are stacked a plurality of rectangular bars or prisms, ll-Il inclusive, composed of light-transmitting material. As is best seen in Fig. 2, the stack of bars lI-l'l is supported on a lower horizontal metal bar i8 and is held against lateral displacement by means of a cover sheet I9 of glass or plastic material. The metal bar i8 and the lower portion of sheet I9 are secured to the mounting plate l0 by means of a plurality of bolts 20, while the upper edge of the sheet I9 is retained byY means of a U-shaped metal strip 2| having a rear flange engaging mounting plate l0 and a iront flange engaging the upper edge of sheet I9. A narrower strip 22, which may be of resilient material such as rubber or felt, is also positioned oh top of the stack, so that the bars may be forced iirmly together between strip 22 and metal bar I8.

Each of the plastic bars lI-I'l is composed of a light-transmitting material having a high index of refraction, preferably a transparent plastic resin. For example, satisfactory materials for this purpose include polymerized derivatives of methacrylic or acrylic acid, such as the materials known commercially as Lucite or Plexiglas The front face of each of the bars adjacent the cover sheet I3 is treated to provide a highly efficient light-emerging surface. Preferably, this front face is polished and cemented to the inner surface of sheet I9, this inner surface being translucent. Alternatively, the cover sheet i9 may be transparent and the front face of each bar may be etched or otherwise treated to provide a translucent light-diifusing surface. The remaining three faces of each bar are treated to provide subsuantially complete internal reflection of light transmitted axially therethrough. This is preferably accomplished by providing highly-polished surfaces on these three faces, and in some cases it may also be desirable to coat these surfaces with a white or silver reflecting material.

As previously mentioned, the cover sheet I3 is 'translucent or transparent and may be made of glass or a suitable plastic. As shown in Fig. 1, it has a plurality of horizontal scales thereon, each scale being positioned directly in front of one of the plastic bars. The scale markings and numerical indicia may be painted, engraved or embossed on the sheet, and they are preferably opaque so as to stand out in relief when back-lighted by light emerging through the front face of the adjacent plastic bar.

The movable Vscale index comprises anarrow vertical strip' `of v.glass or plastic material vwith a vertical index line 2'! marked thereon, and supported at its upper edge from a metal bracket 28. The bracket 2B has a pair of apertured, downwardly-extending ears 29 which areslidably supported by a rod 3!) mounted in rear of, "and parallel to the mounting plate l il. Asmall -rivet 23 is also secured near the 4lower endoffstrip Y2t with a round head resting .on sheet +9. The movable index assembly is thus slidably supported at three points for horizontal movement Yacross the face of the dial sheet 19. It is actuated by means of a cord drive mechanism comprising .1a pair of pulleys 3l, mounted at opposite ends of .the .plate H3, over which Apasses :a Vdrive cord 32 to which an upwardly-extending ear .33 .on the Ybracket .28 is attached. .The drive cord 32 `is `of icourse operated by the .electrical instrument .for which Vthe dial is calibrated, Ain this case -the variable tuning `mechanism of the radio receiver (not shown).

For the purpose of illuminating a selected .one

vof the light-transmitting .bars I i-H, .a corresponding ,number of `electric lamps 35-.6il .are .positioned opposite .the -respective left-hand ends .of the bars. These lamps are conventionally .represented .as 4being of the miniature dial type .with asingle-point bayonet base. .The .lamps are mounted .in va vertical metal strip 42, .in sockets suitably providedtherein. The ends of the plastic .bars .adjacent the lamps .are ,perpendicular to theaxes thereof and highly-polished so as to pro- `vide Vmaximum `transmission .of 'light through Ythe ends. Y

,As seen in Fig. 3, the .strip 142 Ais removably secured by thumb screws 113 to an .apertured Iescutcheon plate A4 which is Vmounted in .front of the .dial assembly. The plate M may have a transparent plastic sheet 55 secured across the aperture, Yby means of a clamping ring 46 and machine screws '47, in order to protect the .dial ,assembly from vdirt and mechanical injury. In-

dividual contact springs 50-56 are suitably mounted .so as Yto make contact with .the base .contactsof the respective lamps. As shown, the springs 5D-56 are secured by means Aof rivets to an insulating strip .51, which is 'in turn fastened to the metal bar 42 by means .of machine .screws .58.

In .orderthat the light from each of the 'lamps 13E-4| may .be directed only .upon the Apolished end ofthe plastic bar which is to 'be illuminated by it, a metal shielding plate @D is interposed between nthe two. .As best seen in Fig. 3, the Atip end of each .of the lamps ts freely into .a socket in the plate .6B which communicates with an aperture .Si of reduced diameter and aligned with the axis of the adjacent bar. The shield plate B is suitably secured to mountingr plate 1U, .as by welding, and its upper end also supports .the ange strip 2l. Another shield plate 5.9 :is .also similarly mounted at the .right-hand end of the .dial assembly, as shown Ain Fig. 3. This plate 591s not apertured in the illustrated 'form ,of theinvention, but its inside surface may v -be polished .or coated to reiiect back any light emerging through the adjacent polished vends of .the .plastic bars .lil-ITI., thereby improving the `uniformity of .scale lighting.

shown in the .simplied circuit vfsliagranrl 0i Fig. Ll, a rotary selector switch 62 is provided for selectively energizing any one of the lamps .S5-4| from a suitable power source, represented by a transformer 63. The same shaft which actufates the selector-switchdiZ Afislalso preferably connected to -the band-switching.mechanism of the receiver. In this way, only the selected scale opposite one of the'bars Il-I'l is illuminated at any one time. In the drawing, the bar I3 is represented 'as being illuminated, causing the figures and markings on the adjacent scale to `.stand `out in .bold relief and clearly indicating :the selected ftuning band of the receiver.

fIt will thus be -seen that we have provided a simple and eective means for selecting any one of a plurality ofscales on a multi-scale dial structure 'which requires no mechanically-moving parts. The indirect illumination of the selected scale not only provides-ia pleasing appearance but minimizeseyestrain on .the part ofthe observer.

fI-t willV beobvious that numerousmodications `may ybe made Iin .the structure vwithin the .scope of our invention. For example, where the indicating scale Iis .relatively long,.it .may be desirable to provide anotherset of identical .lampset the opposite ends of the light-transmitting bars .in -order `to .provide more -uniform .illumination .throughout Athe length Vof leach scale. In this case, .the shield plate .59 may be .identical .to .plate .56, and .the .pairs of ldial lamps .opposite .the .ends

of .eaoh A.bar are then selectively energized Vin parallel from the powerA source. In the illustrated form of the invention, in which vthe .scale .indicia are .carried by the translucent .dialsheet im, .it is .desirable that this sheet be fi-n close .optical contact with the adjacent faces of each of the 'light-.transmitting bars and that `it be composed .o'f a .plastic material having the same index `o'frerac'tion to assure vthat the illuminated area will appear to have clean, .'sharply-dened edges. However, in certain other modifications, it maybe desirable to print, engrave or emboss the scale indicia -directly upon the faces of the strips I'l-fl themselves, in which instance their -faces may themselves be made light-dilusing. 'It will also be apparent that various color effects may readily be produced 'by using color lters between the dial `lamps and plastic bars, or 'by using colored lamps, or by making the plastic `bars themselves of colored material.

As another modification, 'the dial surface 'formed by the front faces oi the plastic bars may 'be curvilinear instead or planar as illustrated. Since these and other obvious modications will readily occur 'to 'those Vskilled in 'the art, we Vtherefore desire 'it 'to be understood that the appended claims are 'intended to cover 'any Vsuch modifications within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters .Patent of the United States is:

1. An illuminated multi-scale dial structure comprising a plurality of selectively illuminable elongated parallel prisms of transparent plastic resin material having a high index of refraction, all the `faces of each ,prism being polished so las normally to provide substantially total internal reilection of light transmitted axially therethrough, one face of each of said prisms being contiguously arranged to form a continuous surface, a dial sheet of plastic resin material having substantially the same `high ind-ex of refraction and having an inner translucent surface in close optical contact with each of lsaid contiguous faces, and a. plurality-'oi groups of scale indicia on said sheet, each group being positioned adjacent one of said contiguous faces and arranged to be illuminated in relief by light diffused through said sheet.

2. An illuminated multi-scale dial structure comprising a plurality of selectively illuminabl elongated parallel prisms of transparent plastic resin material having a high index of refraction, all the faces of each prism being polished so as normally to provide substantially total internal reection of light transmitted axially therethrough, one face of each of said prisms being contiguously arranged t0 form a contiguous surface, a dial sheet of plastic resin material having substantially the same high index of refraction and having an inner translucent surface cemented in close optical contact With each of said contiguous faces, a plurality of groups of scale indicia on said sheet, each group being positioned adjacent one of said contiguous faces and arranged to be illuminated in relief by light diffused through said sheet.

LUIZ G. MALHEIROS. LLOYD E. MONCRIEF.

REFERENCES CITED The following references are of record in the 10 file of this patent:

UNITED STATES PATENTS Number Name Date 2,132,094 Brodton Oct. 4, 1938 15 2,159,095 Modan 1 May 23, 1939 2,367,572 Hayward J-an. 16, 1945 2,446,674 Sproul Aug. 10, 1948 

